Hypodermic syringe



HYPODERMIC SYRINGE Julius V. Magash, Woodridge, and Charles Messineo,Lyndhurst, N. J., assignors to Becton, Dickinson and glompany,Rutherford, N. J., a corporation of New ersey Application May 20,1952,Serial No. 288,784

Claims. (31. 1zsz1s This invention relates to a structurally andfunctionally improved hypodermic syringe; the present application beinga continuation in part of our prior application for United StatesLetters Patent, Serial No. 221,220, filed April 16, 1951, now Patent No.2,73 6,992, entitled Hypodermic Syringe and Method of Making the Same.

By means of the present invention a syringe assembly is produced whichwill be of the all-glass type and which will have a long effective lifedespite the fact that it may be subjected to repeated cleaningoperations involving the use of detergents, repeated sterilizations andother uses which ordinarily decrease or destroy the usefulness of suchan assembly.

A further object is that of furnishing an apparatus of this nature inwhich there will be substantially no danger of effective leakageoccurring between the barrel and plunger even although highly fluidmedicaments are employed.

An additional object is that of providing a syringe assembly which maybe produced at a relatively nominal figure and which will meet allstandards of the medical profession.

With these and other objects in mind reference is had to the attachedsheet of drawings illustrating one practical embodiment of the inventionand in which:

Fig. '1 is a side elevation of the syringe;

'Fig. '2 is a sectional side view of the assembly taken along the line22 and in the direction of the arrows as indicated in Fig. 1;

Fig. 3 is a sectional side view of the barrel portion with parts of thesame shown in greatly exaggerated form; and

Fig. 4 is a side elevation of the plunger with the characteristics of,the latter again illustrated in an exaggerated manner.

Referring primarily to Figs. 1 and 2, the numeral 5 indicates theplunger which in the usual manner may be provided with a rear oractuating portion 6 in the form of a thumb contacting surface. The bodyof this plunger extends into the bore of a barrel 7. The latter, inaccordance with conventional design is conveniently provided adjacentits open rear end with an outstanding flange portion 8 of suitableconfiguration. Its forward end preferably terminates in a tip 9 uponwhich any suitable fitting 10 may be secured so as to mount a needle.The face of the barrel receives indicia 11. The latter includessub-divisions indicative, for example, of cubic centimeters and minums.These sub-divisions serve to register with the forward end of theplunger so that a physician will be aware of the dosage which is beinginjected.

Both the plunger and the barrel are formed of a suitable glasscomposition and the barrel is constructed in accordance with theteachings of the afore-identified application. The bore 12 of the barrelis unground. Therefore, to all practical intents, the body of the barrelmay be clear so that the interior of the bore is readily visible if thebarrel be formed of a composition such that a greatly exaggerated.

i Patented May 21,

transparent unit results. The only optical obstruction will be thepossibilityof air bubbles which, due to the shrinking of the barrel andthe fact that it is not ground, will not provide objectionable airlines. As shown especially in Fig. 2, the barrel bore adjacent its rearor open end is preferably flared to a slight extent as indicated at 13.Such flaring will be located wholly beyond the part of the bore whichreceives the medicament; the sealing fit between the plunger and boreoccurring at points forwardly of this flaring. I

In accordance with the present teachings, those particles which extendinwardly of the bore face prior to the conclusion ofthe manufacturingoperation will have been removed. This removal will preferably have beeneffected by selecting a plunger of proper size, applying a suitableabrasive to the parts and introducing the plunger into the bore. Withsuch introduction and continued relative movements of the partsoccurring, any minute or discrete particles extending into the bore willbe severed from the barrel body. Thereafter, the barrel bore will becleaned and all abrasive and particles of material removed therefrom.Consequently, and as shown in a greatly exaggerated manner in Fig. 3,areas 14 in the nature of islands will be present on the barrel surface.

These will almost always be microscopic in size. Ac-

cordingly, for all practical purposes, the barrel may be the plane ofthe bore. An abrasive having been employed,

it may impart to these minute areas a satiny finish. Where, of course,the particles are broken off so that slight cav-' ities 15 exist, nosuch finish will be imparted. Again,

it will be understood in Fig. 3 that the area of the cavities and theirdepth has, for purposes of illustration, been Certain similardepressions of a shallow nature may occur in the barrel bore as aconsequence of the manufacturing method which is involved. In any event,none of these areas will have any detriw height (for example, three totwenty .00001"). Grind' ing might, in theory, be limited to the bearingsurface of the plunger and the parts adjacent thereto. As a practicalmatter such grinding extends preferably throughout the entire majorportion of the plunger as shown in Fig. 4. That plunger is divided intozones 16 to 20 inclusive. The rear zone 16 is tapered in the directionof the actuating portion 6 to a slight extent (for example .0002). Thebearing portion 17 is as nearly truly cylindrical as possible. Itextends through approximately fifty percent of the effective plungersurface. Zone 18, forwardly of that hearing portion may taper towardsthe forward plunger and by approximately .0005". Zone 159, beyond zone18, may taper in the same direction by approximately .004". The extremeouter end zone 20 may have a length of around V and be tapered to extendat an angle of thirty degrees with respect to the plunger axis.

By providing the initial tapered area 20 the plunger may be readilyintroduced into the flared end 13 of the barrel. Incident to thetapering embraced in areas 19 and 18 it is found that the plunger ridesfreely within the barrel bore. Also, no objectionable sharp edge orshoulder exists in these areas. The area of the bearing surface 17 isadequate to assure a straight guided movement of the plunger and a verydesirable sealing action. The taper arsaess incorporated in area 16provides a free action of the parts even when they are subjected tostrains such that minute distortions of the assembly occurs.

It has been found that by employing a barrel having a bore which issmooth and presents the characteristics of unground glass and using thatbarrel in conjunction with a ground plunger an extremely desirableassembly is furnished. The parts have no tendencies to bind with respectto each other. Also, by having the hearing portion 17 of the plungerembrace an overall length of the nature specified, a very proper sealresults. This seal will not alone prevent squirt backs, but undercontinued use, involving repeated cleanings and sterilizations of theassembly, the seal will remain effective. In this connection it will beunderstood that due to the unground finish of the bore, chemicals willnot attack the surface of the latter. Also, with regards to the bearingportion of the plunger, such changes as occur on the surface incident tosterilization, the use of detergents, etc., will not detrimentallyaffect that surface during the life of the assembly due to the enlargedarea of the seal. Therefore, an apparatus is produced which may besatisfactorily employed for a far greater number of injections than hasheretofore been possible in connection with all-glass syringes. Aspreviously brought out, the barrel is in effect clear so that thephysician may view the medicament within the same. In order that thereshall be no error in connection with the amount of plunger projection,the outer end of the latter may be provided with an indicating mark orline 21 produced for exampleunder the action of heat-by an ion exchangewithin end 20. As is obvious, by resorting to such an expedient, nouncertainty will occur in determining precisely the position of theinner plunger end within the barrel bore.

Thus, among others, the several objects of the invention are shown.Obviously, numerous changes in the structure and rearrangements of theparts might be resorted to without departing from the spirit of theinvention as defined in the claims.

We claim:

1. A hypodermic syringe assembly including in combination and in itsultimate form a glass piston body comprising a barrel-entering portionand an actuating portion, said barrel-entering portion having an area ofuniform diameter and presenting a ground surface throughout itseffective length, a glass barrel having a bore containing said enteringportion, such bore presenting a smooth, chill surface throughout itslength and said surface being interrupted solely by spaced island areas,the spacing being such that said barrel is--in effect-transparent.

2. A hypodermic syringe assembly including in cornbination and in itsultimate form a glass piston body comprising a barrel-entering portionand an actuating portion, said barrel-entering portion having an area ofuniform diameter and presenting a ground surface throughout itseffective length, a glass barrel having a bore containing said enteringportion, such bore presenting a smooth surface throughout its length,and said surfaces being interrupted solely by island areas spaced fromeach other to an extent such that said barrel is--in efiecttransparent.

3. A hypodermic syringe assembly including in combination a plungercomprising a bore-entering body portion, the face of said portion beingground to present a sealing surface extending between ten and fiftypercent of its entire length, a barrel containing within its bore saidplunger portion, said bore being of constant diameter throughout itsoperative length, a smooth face defining the inner surface of said boreto slidably contact said plunger throughout its ground face, said facebeing unbroken except for spaced islands, the spacing being such thatsaid barrel is--in effect--transparent.

4. A hypodermic syringe barrel presenting a plungerreceiving bore, saidbore being of constant diameter throughout its operative length, asmooth face defining said bore and said face being unbroken except forspaced islands and the spacing of said islands being such that saidbarrel is--in effect-transparent.

5. A plunger for use in a hypodermic syringe assembly, said plungercomprising a body circular in cross section and the effective length ofwhich is to enter the bore of a barrel, a cylindrical bearing portion ofsubstantially constant diameter disposed intermediate the ends of theplunger body and providing approximately fifty percent of the over-alllength of such body, such plunger being tapered rearwardly of saidbearing portion and also tapered forwardly of the same, the zone of thelatter tapering being defined by surfaces extending at increasing anglestowards the plunger axis in the direction of the outer end of the same.

References Cited in the file of this patent UNITED STATES PATENTS730,557 McElroy June 9, 1903 772,114 Pappenheim Oct. 11, 1904 1,174,745Lilly Mar. 7, 1916 1,652,894 Gunther Dec. 13, 1927 1,863,785 DickinsonJune 21, 1932 2,392,104 Smith Jan. 1, 1946 2,577,818 Shaw Dec. 11, 19512,618,264 Bloxsom Nov. 8, 1952 2,641,093 Kolodny et al. June 9, 1953FOREIGN PATENTS 2,130 Great Britain Jan. 30, 1908

